ARS scientists are unraveling a biochemical communication pathway that enables plants to cope quickly with drought, heat, cold, pests and other environmental stresses. Unraveling the complete pathway—a complex chain reaction—should help scientists breed plants better able to withstand environmental stresses. ARS scientists discovered and cloned two genes for an enzyme that seems to trigger a stress signal. In plants under stress, this enzyme produces GABA, for gamma-aminobutyric acid, within minutes. The enyzme may function as a thermostat: The more stress, the more GABA is released. When stress starts to decrease, so does the GABA level. The scientists genetically modified a plant named Arabidopsis—a "lab rat" of the plant world—to test GABA's role in plant development and responses to environmental stress.
Climate Stress Laboratory, Beltsville, MD
Frank J. Turano, (301) 504-5527, fturano@asrr.arsusda.gov

The Asian hive bee, Apis cerana, stores a surprisingly large amount of an oily compound in an unexpected place—its venom sac. Scientists are interested in the compound, called eicosenol, because it may be an important ingredient in an alarm pheromone. Bees use alarm pheromones to signal other bees to attack intruders. Until now, pheromones had never been found in bee venom. Other honey bee species apparently store their pheromones in spongelike tissue at the base of their stingers. ARS scientists collaborated with British and Brazilian researchers to analyze more than 300 Asian hive bees from Hong Kong, Malaysia, the Philippines, India and Japan. They found that the honey-making Asian hive bee has 50 to 100 times more of the pheromone component than other bees studied so far. Scientists still are not certain how the A. cerana uses the chemical but suggest the bee might tag potential intruders, thus alerting hivemates. Further research may uncover the chemical's value to Asian hive bees. Those studies may also reveal ways the compound might be used in this country to help our domesticated European honey bee, Apis mellifera, fend off harmful mites that have devastated many U.S. honey bee colonies.
Carl Hayden Bee Research Center, Tucson, AZ
Justin O. Schmidt, (520) 670-6380, ext. 109, joschmid@u.arizona.edu

Using hydroponics, ARS scientists have produced strawberry plants that yield as much fruit as plants grown in soil fumigated with methyl bromide. That's good news for strawberry growers worldwide who use the fumigant to control soilborne insects, diseases and weeds. Because the chemical has been named an ozone depletor, it will be phased out over the next several years. If an effective alternative isn't found, annual production of field-grown strawberries will be cut dramatically in California and Florida, the major producing states. One alternative could be hydroponics—growing plants in a water and nutrient solution without soil. From hydroponically grown plants, ARS scientists harvested ripe strawberries twice a week from December to May. Fruit quality and taste were excellent, and the few foliage pests were controlled with natural agents. Growers may recoup high initial setup costs for hydroponic farming by producing a higher-value product, increasing yields and spending less money on pests and diseases. In addition, weather isn't a factor that limits greenhouse crops, and hydroponically grown berries reduce labor costs.
Appalachian Fruit Research Station, Kearneysville, WV
Fumiomi Takeda, (304) 725-3451, ext. 212, ftakeda@afrs.ars.usda.gov